The mouth-piece and neck are basically made of shibuichi (alloy of silver and copper). The bowl and the end of the mouth-piece are plated with silver so as to make a color contrast. The figure engraved on the mouth-piece is kappa (a creature in Japanese folklore). The letters depicted beside kappa (cf. the picture below) shows that the kappa was engraved for Katsura Bunraku VIII, a famous storyteller of rakugo (Japanese traditional comic storytelling) in the Showa period.